Strange problem with Danfoss heating controls

[sonnyikea]

Ok, so last night I tried to replicate the problem. I had no joy, the system worked flawlessly through all combinations.

I woke up this morning and the same issue occurred. The HW was off. The room stat was calling for heat. The RX1 light was on. The programmer was on for CH only. No boiler firing.
I opened the junction box to the valve. It's just a straight one to one connection. Everything goes through the wiring centre.
View media item 51169
The grey and white wires were live but the orange wasn't. Unfortunately I couldn't find my multimeter (I know this was requested and is probably the key to working out the problem) so I just used an electric screwdriver to check the current.

I opened the wiring centre and checked which wires were live. According to the diagram I linked to earlier in the thread all the currents seemed fine to me except for the link to the orange wire at the valve (which made sense). The room stat connections (2&3) were live. The timer connection (9) was live. The grey and white wires from the valve were live (4&7).

Turning the hot water on fired the boiler as the cylinder stat was calling for heat. The rads heated up (as they should because at this stage the HW and CH were on and both stats were calling). The orange wire was now live, white and grey remained live. I turned off the HW and the orange wire went dead, white and grey remained live.
I turned off the CH and turned on the HW - White was dead, Grey and Orange were live, boiler was firing.
I turned off the HW and turned on the CH - Grey, White and Orange were live and the CH operation returned to normal.

Something somewhere in the valve isn't right but I'm not sure what.

The wiring centre is below but not sure what you will make of it:
View media item 51170

 

[doitall]

I know my eyes are bad and desperately need an operation, but I'm damned if I can see a white and orange wire in either pic.

From what you say everything is working except the end switch.

Take the actuator off and try it, then suspect the valve body is not opening fully.

 

[D_Hailsham]

I opened the junction box to the valve. It's just a straight one to one connection. Everything goes through the wiring centre.

When I said 'junction box' I really meant the wiring centre; I didn't anticipate the valve connecting via a separate junction box.

View media item 51169
The connections in the valve junction box look a bit strange. There is a hidden earth wire in the black cable, but it doesn't appear to connect to the earth wire of the white cable. This seems to connect to the orange from the black cable.

Which cable entering the wiring centre is the white cable from the valve?

 

[sonnyikea]

So in the first picture the orange wire is on the left at the bottom. This links to the yellow/green which in turn is fed to number 6 in the wiring centre.

The white wire is actually the white/brown wire next one up from the bottom on the left which links to the brown on the right. This brown is then attached to number 4 on the wiring centre.
(Left side of the connector is the actuator, right side is the wiring centre)

So if the valve doesnt move the whole way that causes the electrical connection to fail and hence the orange won't become live? With the actuator off the orange should become live because it will have no mechanical resistance? Excuse my ignorance but the valve operation alludes me.

Edit: The actual cable that links the actuator to the wiring centre is the one with the red tape on it that you can see in the wiring centre picture at the bottom.

Note: the wire on the right is just normal flex that was used to extend the actuator cable to the wiring centre. Colour coding of the cables doesnt represent the real world colour coding. i.e. earth colours aren't earth. I know but I didnt install it.

 

[ianmcd]

At last you posted what was wrong the constant clicking sound is your answer you havent wired in HW off from your programmer

 

[sonnyikea]

At last you posted what was wrong the constant clicking sound is your answer you havent wired in HW off from your programmer

The clicking went away when I replaced the actuator.
The HW off is wired in. That's number 8 in the wiring centre from the programmer and 7 from the valve. 10 is HW on and 9 is CH on from the programmer.

Don't forget this system has been in for a few years and all worked fine. It's just this one scenario that is causing me problems.

 

[doitall]

Was going to say the HW off is in 8.

for the record.

The white is the brown in 4.

The orange is the G>Y in 6.

The grey is the Bk in 7.

The HW off is in 8.

As said try it with the actuator removed from the valve, looks like the valve is sticking and not fully opening.

 

[sonnyikea]

As said try it with the actuator removed from the valve, looks like the valve is sticking and not fully opening.

Thanks - so the mechanical movement of the valve makes the electrical connection to the orange? If the valve doesn't move the whole way this connection won't occur and result in what I am seeing?

Would the turning off of the CH, turning on of the HW, turning off the HW and then turning the CH on again put enough force on the valve to overcome the sticking?

 

[doitall]

If the valve isn't fully opening at best you'll wreck the gears in the new actuator.

 

[sonnyikea]

Thanks - it'll be tomorrow morning again before I can try with the actuator off. Will let you know how I get on!

 

[sonnyikea]

I managed to replicate the issue last night. So I spent a good while playing around with various settings and worked out the scenario that causes the issue. This was with the actuator off.

If the HW and CH are on and the HW goes off the CH never fires. The actuator doesn't move when the HW goes off. That's the root cause of the problem. If the HW is on first and then goes off and then the CH comes on everything works fine. Likewise if the CH is on first and then goes off and then the HW comes on everything works fine. If the CH is on and the HW comes on both heat. If the HW then goes off, again the actuator doesn't move and the CH never comes back on again. If, in this last scenario, the CH goes off and then the HW goes off and then the CH comes on again the CH works. This last point is, coincidentally, why I was only seeing the issue in the morning. I believe in the evening the CH was satisfied before the HW so the CH was off when the HW went off when the CH was called upon again from the room stat it worked. In the morning the HW was satisfied before the CH and so I was seeing the CH no longer firing. This was all down to timings and water usage (showers during the day meaning HW was on for longer in the evenings than the morning).

So the question is, why? Have I something connected incorrectly? The only thing I can work out from the wiring centre is that the pump has an overrun, might this be causing a problem? The pump should, according to the diagram, be connected to 13. You will see that this is blank in the image I posted. What you can see is the Pump Live connects directly to the Boiler Perm Live via a separate clear coloured connector (the pump and boiler cables are the two dirty looking ones coming into the wiring centre bottom right). From what I have read this is the correct way to wire in the pump for boilers that have an overrun facility.
View media item 51170
Or is this a red herring and it is something else?

 

[doitall]

Have you got a multimeter and know how to use it safely.

 

[sonnyikea]

I do but I've not used one on AC before. Probably time to call in the pros.

At the moment I have changed the timings so the HW comes on and does it's thing and then the CH comes on, so the two are separate. Should give me a viable workaround.

 

[ianmcd]

I still think you have a problem with the HW off side of your controls, the clicking that you had previously is a classic sign that the HW off is a problem, your system seems to be wired correctly but I wonder if you have a programmer fault with the HW off, the way the system works is that you actually have two switch wires for HW off, one gets power when the programmer switches the HW to off the other switches when the HW cylinder stat is satisfied it sounds as though only the HW cyl stat switch is operating it sounds as if the timed switch on the programmer isnt doing what it is supposed to do , could be a dodgy connection or faulty programmer

 

[doitall]

In the htg only mode, there should be 230Vac on the grey and Orange, I was going to get that checked but if the OP is not safe with 230V live stuff, getting an expert in is best.

The clicking sound is the Valve gear worn or bent, usually because the valve is sticking.